Amoxicillin (Amoxil®, Polymox®, Trimox®) STI Treatment

STI Standards

Midwives may independently prescribe, order, and administer drugs in the community, hospital or other sites of midwifery practice to treat sexually transmitted infections for clients in case, as designated under specialized practice certification. Midwives without specialized practice certification in sexually transmitted infections management are required to refer their clients to an appropriate health care practitioner for treatment. 

Penicillin antibiotics act as a broad spectrum bactericidal against many gram-positive and gram-negative microorganisms. This is achieved through the inhibition of biosynthesis of cell wall mucopeptide.

Indications and Clinical Use:

For treatment of asymptomatic or symptomatic chlamydia trachomatis and neisseria gonorrhea in pregnancy and the postpartum. It is also for treatment of uncomplicated asymptomatic or symptomatic urinary tract infections (UTIs) in pregnancy and the postpartum caused by Enterococcus faecalis, Escherichia coli, or Proteus mirabilis.(Please refer to the CMBC Standards, Limits and Conditions for Prescribing, Ordering and Administering Drugs)


Documented hypersensitivity or allergy to Amoxicillin or any other Penicillin antibiotic or component of the formulation.

Warnings and Precautions:

Reduces efficacy of oral contraceptives; adjust dose in renal impairment; may enhance chance of candidiasis. Prolonged use may result in fungal or bacterial superinfection, including C. difficile associated diarrhea (CDAD) and pseudomembranous colitis; CDAD has been observed >2 months post-antibiotic treatment. Use with caution in asthmatic patients.

Breastfed infants may develop slightly looser stools than normal. Modification of bowel flora and allergic sensitization of the infant may occur.


Human Data Suggest Risk in the 1st and 3rd Trimesters. There is some evidence that exposure during organogenesis is associated with oral clefts and necrotizing enterocolitis when used in preterm labour however, the absolute risk is very low and requires confirmation.


Limited Data – compatible.
Less than 0.95% of the maternal dose is secreted into milk which is less than 0.5% of a typical infant dose of amoxicillin. There have been no harmful effects reported.

Adverse Reactions:

Upset stomach, diarrhea, vomiting, vaginal infection and/or mild skin rash. The following should be reported to a medical practitioner immediately: severe skin rash, itching, hives, difficulty breathing or swallowing, wheezing, unusual bleeding or bruising, sore throat, painful mouth or throat sores, jaundice and/or diarrhea.

Dosage and Administration:

Chlamydia Trachomatis:
Amoxicillin (Amoxil®, Polymox®, Trimox®): 500 mg orally every 8 hours (tid) for 7 days. May be taken with food.

Onset of Action:

Oral: Rapid; food does not interfere with absorption.

Duration of Action:

Peak serum concentrations usually attained within 1–2 hours.
Half-life: 1-1.4 hours.